Trial Balance: Unadjusted, Adjusted and Post-Closing, and How Auditors Use It

A trial balance is a list of every general ledger account and its balance at a point in time, with debits in one column and credits in another. If the books are in balance, the two columns total the same amount. For bookkeepers it is a check at month-end. For auditors it is the spine of the engagement file: every lead schedule, every adjustment and every line of the financial statements traces back to it.

This guide covers what a trial balance contains, the three versions you will see during the year-end cycle, how audit teams use the trial balance to build the file, and the errors that a balanced trial balance can still contain.

What is a trial balance?

A trial balance is a report generated from the general ledger that lists each account with its ending debit or credit balance, and totals both columns. Most accounting systems produce it on demand.

A typical trial balance has these columns:

The order usually follows the chart of accounts: assets, liabilities, equity, revenue, then expenses. Some systems show a single signed column instead, with credits as negatives, in which case the column totals zero.

What a balanced trial balance proves, and what it does not

A trial balance that balances shows that total debits posted equal total credits posted. That is all. It does not show that:

• entries were posted to the right accounts
• all transactions were recorded
• transactions were recorded in the right period
• amounts are valued correctly under GAAP

A journal entry posted to the wrong expense account, a missing invoice, or an entry recorded twice on both sides will all leave the trial balance in balance. This is why an auditor treats the trial balance as a starting point for testing, not as evidence of correctness.

The three types of trial balance

Unadjusted trial balance

The unadjusted trial balance is run after routine transactions for the period are posted but before period-end adjusting entries. It reflects what the day-to-day accounting has recorded: sales, purchases, cash receipts and disbursements, payroll.

It usually lacks accruals, deferrals, depreciation for the final month, inventory adjustments, and estimates such as the allowance for credit losses.

Adjusted trial balance

The adjusted trial balance is run after management's period-end adjusting entries. These typically include:

• accrued expenses and accrued revenue
• prepaid expenses amortized to expense
• deferred revenue recognized
• depreciation and amortization
• inventory count adjustments and reserves
• allowance for credit losses under ASC 326
• income tax provision

The adjusted trial balance is what management uses to prepare the financial statements. In an audit, this is usually the version the client gives the auditor as the starting point, though it is often still called the "client trial balance" or "preliminary trial balance" because audit adjustments may follow.

Post-closing trial balance

After the books are closed for the year, revenue, expense, gain and loss accounts are closed to retained earnings (or to net assets for a not-for-profit, or to partners' or members' capital). The post-closing trial balance lists only balance sheet accounts, because the temporary accounts are now zero.

Auditors use the post-closing trial balance from the prior year to check opening balances in the current year. The current-year opening balance of every balance sheet account should agree to the prior-year audited closing balance, and opening retained earnings should agree to the prior-year audited ending retained earnings.

Comparing the three

How auditors use the trial balance

Obtaining and agreeing the trial balance

The first step is to obtain the client's trial balance and confirm it is complete and agrees to the general ledger. Practical checks:

1. Foot the debit and credit columns.
2. Agree the trial balance to the general ledger detail for key accounts.
3. Agree current-year opening balances to the prior-year audited balances.
4. Confirm the trial balance date matches the period end.
5. Confirm it is the final pre-audit version, not a draft that management keeps updating.

If management changes the trial balance after it was provided, the file needs a clear record of which version the work was performed on and how later changes were tested.

The working trial balance

Firms typically load the client trial balance into a working trial balance in their audit software or spreadsheet. A working trial balance usually has these columns:

The working trial balance is where audit adjustments are posted and the final numbers for the financial statements come from. It also gives the year-over-year comparison that feeds preliminary analytical procedures under AU-C 315 and the final analytical review at completion.

Mapping accounts

Mapping is the process of assigning each general ledger account to:

• a financial statement line, such as "Accounts receivable, net" or "Selling, general and administrative expenses"
• a lead schedule or workpaper area, such as receivables, revenue or payroll
• sometimes a disclosure grouping, such as property and equipment by class

Mapping decisions affect the financial statements directly. A credit card clearing account mapped into cash overstates cash. A customer deposit account mapped into receivables nets a liability against an asset. Accrued payroll grouped with accounts payable hides a different risk profile. Review the mapping each year, especially for new accounts the client added during the year.

Lead schedules

Each lead schedule pulls the mapped accounts for one area from the working trial balance. It shows the prior-year balance, the current-year unadjusted balance, adjustments and the final balance for each account, with references to the detailed testwork. The lead schedule ties to the trial balance, and the testwork ties to the lead schedule. See audit working papers for how lead schedules fit into the wider file.

Planning and materiality

The trial balance drives planning. Materiality benchmarks such as revenue, total assets or pretax income come from it, and those figures go into the materiality calculator and the documentation under AU-C 320. Because the benchmark comes from preliminary figures, the auditor reassesses materiality if the final figures differ significantly.

Identifying significant accounts

Comparing current balances to prior year and to expectations helps identify accounts with unusual movements, new accounts and accounts with large balances. Together with the risk assessment, this helps determine significant classes of transactions, account balances and disclosures and the relevant assertions. See audit assertions for how assertions link to procedures.

Posting and tracking adjustments

Audit adjustments are posted to the working trial balance and recorded on the summary of misstatements under AU-C 450. Proposed adjustments that management records go in the adjusting column. Those management declines go on the summary of uncorrected misstatements, which is evaluated against materiality.

Keep the working trial balance and the client's books in agreement. After management records the agreed adjustments, obtain a final trial balance from the client and agree it to the audit's final column. Differences mean either an entry was not recorded or something else changed.

Tying out the financial statements

At completion, every line of the financial statements should agree to the final column of the working trial balance through the mapping. Footnote figures should agree to the lead schedules and supporting schedules. This tie-out is a standard step in the completion checklist.

Common trial balance errors

Errors that leave the trial balance in balance

• Errors of omission: a transaction not recorded at all.
• Errors of commission: posting to the wrong account of the same type, such as one customer instead of another.
• Errors of principle: recording a capital expenditure as repairs expense.
• Compensating errors: two errors that offset.
• Duplicate entries: the same entry posted twice, both sides.
• Reversed entries: debit and credit swapped, which doubles the error but keeps the balance.

Errors that throw the trial balance out of balance

• a one-sided entry, possible in some older or spreadsheet-based systems
• a transposition error (for example 5,640 entered as 6,540), which produces a difference divisible by 9
• an amount entered on the wrong side of a single account in a manual trial balance

Modern accounting systems rarely allow an out-of-balance trial balance, so the errors that matter most to the auditor are the ones that keep it in balance.

Red flags worth investigating

• suspense, clearing or "ask my accountant" accounts with balances at year-end
• accounts with an abnormal balance, such as a credit balance in receivables or a debit balance in accounts payable
• opening balances that do not agree to the prior-year audited figures
• new accounts with large balances and vague names
• a retained earnings rollforward that does not reconcile to net income and distributions
• intercompany accounts that do not net to zero across entities

Each of these can indicate a classification problem, a cutoff problem, or an entry that bypassed normal controls. These accounts are relevant to journal entry testing under AU-C 240.

Documentation tips

• Keep the client trial balance as received, with its date and the person who provided it.
• Record the version used and any later versions, with a reconciliation between them.
• Document the mapping and review it for new or renamed accounts each year.
• Cross-reference each lead schedule to the working trial balance.
• Agree the final financial statements to the working trial balance and keep that tie-out in the file.

These steps are routine, and skipping them can leave a reviewer unable to follow the file. AU-C 230 expects the documentation to let an experienced auditor understand the work performed.

FAQ

What is the difference between a trial balance and a balance sheet?

A trial balance lists every general ledger account, including revenue and expense accounts, with debit and credit balances. A balance sheet is a formatted financial statement showing assets, liabilities and equity at a date, prepared from the adjusted trial balance.

Does a balanced trial balance mean the books are correct?

No. It only means total debits equal total credits. Misclassifications, omissions, duplicate entries and valuation errors can all exist in a balanced trial balance.

Which trial balance does the auditor start with?

Usually the client's adjusted trial balance at year-end, after management's period-end entries but before audit adjustments. It is loaded into a working trial balance where audit adjustments are tracked.

Why do auditors check the prior-year post-closing trial balance?

To confirm that opening balances in the current year agree to the prior-year audited closing balances. A difference means something changed in a closed period and needs explanation.

What is trial balance mapping?

Mapping assigns each general ledger account to a financial statement line and a workpaper area. It controls where each balance lands in the financial statements, so errors in mapping become presentation errors.

Sources

• AICPA, AU-C Section 230, Audit Documentation
• AICPA, AU-C Section 315 (as revised by SAS No. 145); AU-C Section 320, Materiality in Planning and Performing an Audit; AU-C Section 450, Evaluation of Misstatements Identified During the Audit
• AICPA, AU-C Section 240, Consideration of Fraud in a Financial Statement Audit (journal entry testing); AU-C Section 520, Analytical Procedures
• FASB ASC 326-20, Financial Instruments, Credit Losses, Measured at Amortized Cost

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AU-C references are to AICPA Professional Standards, paraphrased here; read the standard itself before relying on a requirement. This page is guidance, not professional advice. Report an error